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Forum:Chickenosaurus
Here we will discuss Jack Horner's Chickenosaurus project. We need to know what modifications will be needed to give a chicken back its teeth, tail etc. We also discuss the criticisms about the project. Please give sources for each claim and quote. Progress we make on this forum should be incorporated in the Chickenosaur article. Tail Ancient birds, like Archaeopteryx, had a long reptilian tail. Modern birds still have a . The main focus of Horner's project is to identify the gene(s) that cause inhibition of tail development in the embryonic stage. By changing the expression patterns of these genes, chickens with long dinosaurian tails could be bred. The idea has attracted criticism from many scientists. Sean Carroll, a developmental biologist, has experimented with the development of insects, and these experiments have usually killed them. Hands and Claws Hips I think that creating an animal very similar to Dryosaurus or Hypsilophodon will be pretty easy using this method, since the chicken already has an ornithischian hip structure. Jurassic Park Treasury (talk) 04:56, March 10, 2014 (UTC) Snout In 2011, a scientist managed to create a chicken with a snout. The article is on New Scientist, so you have to register to read, but the article can also be read here. It should be noted that they just switched off the fusion of the premaxilla though. Jurassic Park Treasury (talk) 22:24, December 4, 2013 (UTC) Teeth I've heard that the tooth gene in chickens kills them before they hatch. Can the gene be made non-lethal, or will we have to skip the teeth altogether? And I'm curious to see the regulatory proteins and sequences. Are they on NCBI? Jurassic Park Treasury (talk) 06:15, April 10, 2013 (UTC) Apparently, birds cannot develop functional teeth with enamel. The teeth developed in embryos were merely useless tooth buds. But even if the tooth enamel genes in chickens have disappeared or become pseudogenes, would it be possible to make the pseudogenes functional again? Jurassic Park Treasury (talk) 01:56, April 15, 2013 (UTC) Here is an DNA sequence in the chicken that used to be functional enamelin. Over time, it has become a pseudogene. But if we can find out what made it non-functional, could we potentially undo the point mutations and turn it into a functional gene again? Jurassic Park Treasury (talk) 06:02, April 16, 2013 (UTC) I just compared chicken enamelin with crocodile enamelin on Clustal Omega. It turns out that the chicken enamelin has LOTS of gaps in it. It also has quite a few differences, so I think there will also be a lot of point mutations to detect. Jurassic Park Treasury (talk) 06:15, April 16, 2013 (UTC) :If the enamelin pseudogene in the chicken was compared with the functional crocodile or alligator genes, would it be possible to detect the mutations that made the gene non-functional and reverse engineer it to a functional ancestral state? And if so, could it be done with the AMEL gene too? For the chickenosaur to be a non-avian dinosaur, to me it has to have arms with claws, a long tail AND functional teeth. Ornithomimids are the only exception. Jurassic Park Treasury (talk) 06:41, May 20, 2013 (UTC) I have done some research. Even if you did get some functional enamel genes, you would need to find a way for the genes to be expressed. The only known thing that allows chicken tooth buds to develop is talpid2, which is lethal because it not only allows teeth to form, but also because it screws up organ systems. We will need to find a way for talpid2 to be expressed in the jaws without it affecting other parts of the body. Jurassic Park Treasury (talk) 03:06, March 25, 2014 (UTC) :What about injecting enamel or talpid2 at the right time into the tooth buds? Do you know if anyone tried that? BastionMonk (talk) 13:17, June 3, 2014 (UTC) Well, I have now found out that many enameless species have non-functional enamel genes partially due to the presence of stop codons in the remaining enamelin pseudogenes. Stop codons can be TGA, TAA or TAG. The enamelin pseudogene sequence of the chicken is on GenBank, so I am now trying to find all of the stop codons in it. Then we could remove them. However, in order to avoid confusing normal parts of the sequence with stop codons, I will not count TGA, TAA, or TAG sequences at the end of the ten-nucleotide sections that the GenBank sequences are presented in as a format. For example, this would count as a stop codon in my search: TAGgtcagg However, this would not: gtacaggTAG Would this be a good method to avoid mistaking normal codons for stop codons? If this is successful, I think we could potentially create a functional enamelin gene for the chickenosaurus. Jurassic Park Treasury (talk) 08:26, June 3, 2014 (UTC) :Isn't the stop codon supposed to be on the right-hand side? BastionMonk (talk) 13:17, June 3, 2014 (UTC) :I compared the enamel gene with crocodiles. The simularities were VERY slim. I looked into the article of Sire et al. They also couldn't find good hits when they compared very conserved exones of crocodile ENAM gene with the entire chicken chromosome 4. They found some similarity with that "speudogene" region, but they're not happy with it. They think that the genes for ENAM and AMBN are most likely lost from the bird genome. Chromosome 4 was rearranged just before the last common ancestor of birds. During that rearrangement, the ENAM region was replaced to the edge of the chromosome. Maybe that "speudogene" region contains some fractions of the gene, and maybe not. However, they haven't looked at any ratite genome. So, maybe... :I looked quickly again in the article of Griffin et al., The evolution of the avian genome as revealed by comparative molecular cytogenetics. They compare the chromosomes of different birds and turtles based on chromosome-"paint". They indeed note that in chicken chromosome 4 rearrangements and fusions with other chromos took place. However, the chromosome 4 is still unaltered in Rhea, Emu, Mallard, Muscovy, Californian Quail, Turkey, Pheasants etc. :If that is true, we just have to wait until one of those birds is fully sequenced and get look what their teeth genes look like. BastionMonk (talk) 13:59, June 3, 2014 (UTC) :Of those, I believe that the mallard and turkey genomes have been sequenced. However, I cannot find the gene ENAM in any database. Emus and ostriches sound like good candidates though. I happen to live in a city with a good university, so maybe I could ask a geneticist or evolutionary biologist if they are interested in finding out if ratites still retain their tooth genes. Jurassic Park Treasury (talk) 21:13, June 3, 2014 (UTC) ::That is a very specific subject. Don't think a random geneticist knows that. I wonder how Jack Horner wants to tackle this problem. I BLASTed the crocodile ENAM gene against the entire Avian database. I didn't get any good results. So, I think that chromosome 4 region is not sequenced in enough archosaurs. BastionMonk (talk) 07:04, June 4, 2014 (UTC) Problems A critic said this. "I've seen Dr. Horner's TED talk on this before - I dislike it for many reasons. Foremost is of these reasons is that the idea of reverse engineering a dinosaur from a chicken is a gross misinterpretation of the actual science. Evo-devo studies the evolutionary relationships of organisms. Through complex and truly brilliant experiments researchers are beginning to unravel the directions for 'building' an organism, and how these directions have evolved to create the life we see around us. They are often interested in the genes and gene combinations that code for ancestral traits, however, this is not a search for a way to rebuild dinosaurs. Instead, evo-devo is more a search to understand how/why complex lineages evolve from one state into another." If that is correct, then I suspect that Horner doesn't quite understand the whole evo-devo thing. Another critic also pointed out that Horner seems to follow the discredited notion that "ontogeny follows phylogeny". Jurassic Park Treasury (talk) 06:03, December 4, 2013 (UTC) :This is like saying that microbiology is the study of how cellular mechanism work, not a search for new medicins. And therefore trying to create a new medicine using microbiology is a "gross misinterpretation of the actual science." If Horner was soo wrong he would never been able to publish his plan in NewScientist. :"ontogeny follows phylogeny". It is true that the development ISN'T a 100% repeat of evolution. However, it is in no way discredited. Embryonal development is still used by phylogenists and evolutionary biologists. It is in every textbook about evolution. For example: Freeman S.,Herron J.C. (2004) Evolutionary Analysis (3th Ed.). Page 51, 52. BastionMonk (talk) 11:43, December 4, 2013 (UTC) Dinosaur, or weird chicken? Many critics of the project contend that the chickenosaur would not be a true non-avian dinosaur, but merely a bird with a tail and arms. Atavisms do not change the species of an organism. If you see a miniature horse born with extra toes, do you call that an Eohippus? Jurassic Park Treasury (talk) 00:32, October 22, 2013 (UTC) :Currently, there are no rules about where artificial animals belong on the taxonomic tree. Craig Venter gave his modified Mycoplasma bacterum "Mycoplasma laboratorium". So, modification did change its species. :A modern horse with toes is not Eohippus, because then it would need almost ALL characteristics that Eohippus has. However, if you have a single horse with toes most taxonomics will just call it a horse with an abberation. However, if you have an entire herd of these creatures, they will probably give it a new name since all Equus lack toes. Taxonomic names are more something that are made up by man rather then discovered. :So, what would a chickenosaur be? Well, if it is only one animal, most people will just call it a chicken with a few abberations. However, if you have a reproducing flock of these creatures, they will probably give it a new name. Chickens have no teeth, no tail and no claws. Furthermore, not a single clade of extant birds has these characteristics. So, taxonomics will either have to invent a new clade or place them in an already existing clade (which could be part of the non-avian dinosaur group). BastionMonk (talk) 20:27, October 22, 2013 (UTC) Reproduction Horner has said that if a chickenosaurus was to mate with another chickenosaurus, it would produce a chicken, since the genes themselves have not been changed. Is this true? Jurassic Park Treasury (talk) 02:15, March 6, 2014 (UTC) :In the book he said he is not gonna change the DNA of the chickens. Horner wants to stick a lot of tubes into a developing chicken embryo. At the right stages of development hormones and transcription factors will be put into the embryo. If this is done the right way, the chicken-embryo will develop into a chickenosaur. :Horner and his team will have to discover the right method by educated guesses and trial and error. This is easier done by manually manipulating hormone levels than modifying the hormones' regulatory sequences. It is also saver, because the chickenosaur can't reproduce if it would escape into the wild. :But don't worry. Once the chickenosaur is succesfully created, it is possible to change its DNA such that the chickenosaur-phenotype is also encoded in its genome. But that would be a project an sich. BastionMonk (talk) 09:58, March 6, 2014 (UTC)